1. Key Terms

The following terms and parameters are in order of significance and order when on site.   

There are two types of flight paths: (1) Point of Interest and (2) Rasterized.

(1) Point of Interest (POI) (Flight Path) – Circular shaped flight paths around a property. These are commonly attributed to “oblique” imagery - images taken at an angle. This flight path is best used for capturing vertical 3D features, such as vent pipes, attic fans, building facades and other obstructions. POIs are used for residential and most commercial size solar projects. 

Two types of POI Flights: 

Context Flight – This is the first, and occasionally second drone flight if there’s a lot of vegetation, that encompasses the full context of the site. The proposed project location and all relevant obstructions should always be in frame in the first context flight. The point of interest should be the middle of the site in almost all cases. See flight #1 in the subsequent image. This flight usually has the largest radius. 

Altitude is often above the highest obstruction, which is usually between 50 feet to 70 feet for most residential properties, and up to 150 feet Above Ground Level (AGL) in some regions due to tree height. When mapping large buildings, telecom towers or other tall vertical structures the maximum AGL will be the height of those structures plus approximately 10 feet. Ground mount context flights that require less site granularity can have varying altitudes. Ground mount flights will also include one rasterized flight (see (2) Rasterized below).

1.  Detailed Flight – These are the subsequent flights after the context flight. See flights #2 and #3 in the image on the left. These are smaller circles focused on specific details on site. Flights typically include smaller radii around specific roof planes or clusters of obstructions. Altitude is usually 10 feet above the roof plane or the obstructions being photographed. The proposed project location or structure does not have to be in every frame nor in the middle of the radius. 

2. Rasterized (Flight Path) – AKA grid pattern / lawnmower / row shaped flight paths up and down a property. These are commonly attributed to “nadir” imagery or images taken with the camera facing straight down, which is commonly found in DroneDeploy rendered flights. Rasterized paths are used for larger commercial and ground mount projects. These can also serve as the context flight for small or mid-sized commercial projects. Since rasterized flights are typically flown with the camera facing straight down (nadir), this camera angle makes it difficult to 3D map vertical features. To capture vertical features for projects flown with DroneDeploy, we recommended using “Structures Mode” to capture oblique imagery after the rasterized flight path is completed. 

Overlap – This refers to how much of an object in one picture exists in another. For example, 90% overlap means that 90% of one picture has the same imagery as another. See how the below drone images have most of the building in frame as the next image, just from a different angle.